Inflate 365 steer tires to 125 psi

[Mr_D]

Originally Posted by RVFunlovers

I like my VIair compressor. I agree with checking your coach weight. My front tires run 115.

I have never tried to fill a tire from empty with my VIair compressor. But it you need to bring a front or rear tire up a few pounds the compressor will get it done.

Be sure to check and air up in the morning before driving with no sun hitting the tires. I learned the sun lesson the hard way.

It takes about a minute per pound of increase for the VIair on my front tires. Not bad in my view.

I have never tried airing up from my coach onboard air. Many use an air doubler with the coach air to get the pressure needed.

The VIair compressors are pretty small. They easily fit in your RV/ I ordered the kit that comes with the bag and everything you need like hose and extending hose, etc.... I believe I have the 400. $300 bucks from Amazon. I think the 400 has a little more volume than the 450. I am sure they both would do the job.

The 400 does have a slightly higher volume, but a shorter duty cycle. My 365/70 fronts take 125 and tag (also 365/70's) take 105 as do my 315/80 drives. The 450 RV is what I use.

[Tireman9]

Originally Posted by 777 Driver

Hi Steve,

Exactly why I like my DeWalt, too.

Oh, did I mention that I really like its ability to filter out all impurities from ambient air so that it's only pumping dry nitrogen into your tires?

Take care,
Stu

P.S. I'm joking about the dry nitrogen.

I made my own air "dryer" using filters used when spraying paint. Published a blog post with pictures. BUT you need filters rated for the high pressure you are using. My Harbor Freight filters were only rated 95 psi.

[Mr_D]

Originally Posted by Tireman9

I made my own air "dryer" using filters used when spraying paint. Published a blog post with pictures. BUT you need filters rated for the high pressure you are using. My Harbor Freight filters were only rated 95 psi.

Yep. I was going to use the Harbor Freight one till I read the fine print!

[Gary.Jones]

What nobody has said, but I think is true, there is no mystery in Mr. D running 125psi in his coach. His coach was made by Monaco who made their own chassis and in all likelihood simply is a much heavier chassis on the steers. Because he runs 125 doesnt mean that you need to run 125 in your coach.

Remember, what we are telling you is that you need to know how much load (e.g. weight) is on each tire position (ideally)(or alternately, if you can't get 4 corner weights), then the axle loads a second best. From those loads, then you go to the tire manufacturer load-inflation tables for the specific brand/model tire you have and the tire manufacturer will tell you the minimum safe pressure you should have in your tires for the loads that those tires are carrying. Now, can you put in even more pressure than what the table says..... SURE, but your ride is going to degrade substantially as you go well beyond what is necessary for the loads your tire is going to carry. Obviously, you should determine the loads when your coach is loaded as it will be typically loaded. You need to have the normal stuff you plan to haul on-board, you should fill your diesel tanks to full, you should fill your gray and black tanks either full or to at least half full, and you and your copilot should be sitting in the driver and co-pilot seats while weighed. That is the maximum load your coach should "normally" routinely carry (and you will really be loaded to that level often while you are traveling and just leaving the truck stop after fueling). Now go to the tables and determine tire PSI. Many owners use the load of the heaviest tire position for all the tires on the axle.

Now, many of us don't take the absolute lowest tire PSI from the load tables that are safe, and will usually go a little higher but not inflate to the maximum pressure allowed by the tire manufacturer. You want a margin. The more you inflate your tires beyond what is needed and toward maximum tire pressure, the rougher ride you will give yourself. Can you run your tires at maximum pressure, sure, but you will most likely shake the filling out of your teeth in your half million dollar coach. Yuck!

The most critical tires are the steers. On my Anthem, I carried a bunch of mechanic tools in the front full basement storage bay. With a full tank of fuel, the freezer loaded, and Dee and I sitting in our positions, my front tire loads were literally right at the maximum rating for the axle. Entegra put larger tires on their coaches to give more headroom between the axle loads and the design loads. Back about 2014 and 2015 the loads were close to the max of the axle. Now I have lots of "headroom" on steer tires and axle loads after Entegra used stronger axles and larger tires.

Finally, you do not need to do what is called "chasing tire pressures" as you change geographic or climate zones. You set the tires for "cold" pressures (in the mornings) in average conditions.... Your tires will increase in pressure ~ 20# or more as you travel. Those pressure are factored into the safe margins for tires. I make sure that my tires are set to where I want to run them a day or two before I plan to depart for a 2,000 mile trip out west, and I dont worry about them after (unless the TPMS systems show they are getting hot or the pressure is dropping). Otherwise, the tires take care of themselves as we travel. Tires don't have to be a problem.... load them correctly, inflate to the right pressure, inspect them carefully every once in a while, and drive.

Gary



Gary

[Tireman9]

Originally Posted by Gary.Jones

IMO, Everybody needs to find themselves a high quality "truck Tire Pressure " gauge and use it. What GarySB says is generally correct about the pressures changing on the Viair gauge, but I never depend on the Viair pressure gauge.... the gold standard is a high quality stainless steel truck tire pressure gauge. I keep mine in my step drawer for quick access and accurate pressure checking before each trip. That gauge is the one that I believe!

Gary

Have you checked your "gold standard" gauge against a certified digital gauge? Does it have a certification sticker? What is the date on the sticker?

I have 3 Accutire digital gauges that have been checked against an ISO laboratory certified gauge and all measure within 1/2 psi of each other and the Lab gauge.
You don't need a lab gauge but you do need to have a "Master Gauge' THAT YOU ONLY USE to check your daily gauge against. Using a gauge can result in it going off calibration.
I check my 3 gauges against each other and the chance of all 3 going off calibration the same amount, at the same time is vanishingly small.
Simply making something out of Stainless doesn't mean is is a more accurate gauge.


When I do gauge checks at RV conventions, I usually find 10% to 20% of the gauges checked against my master are off by more than 5 psi.

[Tireman9]

Originally Posted by Mr_D

Yep. I was going to use the Harbor Freight one till I read the fine print!

Granger Supply has some rated for 150 psi.

[Gary.Jones]

Tireman

There is an old saying that goes something like, "If you have one clock, you know what time it is. However, if you have two clocks, you are much less certain of what the time is. I would add, if you have three clocks, then you have no idea whatsoever what "real" time is.... and the same is true with tire gauges. Unless you are using the certified ASO gauge, you really dont know the exact tire pressure. You can calibrate against the known standard, but as soon as you bounce down the road a few hundred miles and the temperature varies over 60 degrees, you are guessing again.

I also have digital tire pressure gauges. They are pretty good. Stainless steel does not make the pressure gauge good.... how accurate it is is the issue. My advice was based on my experience that a really good truck gauge does a consistently good job on telling me what inflation I am running in my coach (same as truck) tires. Just MHO.

Gary

[LWBAZ]

I recently purchased a made-in-the-USA Milton s-986C Tire Pressure Service Gauge. It is a big, hefty gauge – about 14 inches long when not in use and about 18 inches long with the pressure indicator stick extended – see photos below.

A distinguishing feature of this gauge as compared to many others on the market is that it is “re-calibratable,” meaning you can check it against a certified master gauge and re-calibrate it in one-quarter PSI increments – see image below. I haven’t done that yet, but I’m confident the gauge was reasonably accurate from the factory.

The s-986C gauge is available direct from Milton for about $32 or a bit less from Amazon. Be aware the s-986 series comes in a variety of configurations, so check the specs carefully before ordering. More info on the s-986C here:

https://www.miltonindustries.com/gauges/service-gages.html/re-calibratable-tire-pressure-service-gauge-dual-head-straight-foot-chuck-10-160-psi

[Tireman9]

Originally Posted by Gary.Jones

Tireman

There is an old saying that goes something like, "If you have one clock, you know what time it is. However, if you have two clocks, you are much less certain of what the time is. I would add, if you have three clocks, then you have no idea whatsoever what "real" time is.... and the same is true with tire gauges. Unless you are using the certified ASO gauge, you really dont know the exact tire pressure. You can calibrate against the known standard, but as soon as you bounce down the road a few hundred miles and the temperature varies over 60 degrees, you are guessing again.

I also have digital tire pressure gauges. They are pretty good. Stainless steel does not make the pressure gauge good.... how accurate it is is the issue. My advice was based on my experience that a really good truck gauge does a consistently good job on telling me what inflation I am running in my coach (same as truck) tires. Just MHO.

Gary

Funny statement about clocks. But the reason I have 3 is that I am confident that if one goes bad (off calibration) it will be different than the other 2.


Don't know how the temperature changing will result is the gauges going off calibration. I have observed that "stick" type gauges seem as a group to be the most likely to lose calibration. This is because of dirt etc getting on the "stick" part as well as general wear. Even ran into one guy who insisted his stick gauge was correct and all 3 of my digital gauges were equally wrong because he said he cleaned and lubricated his truck stick gauge with WD-40.

[LWBAZ]

Originally Posted by Tireman9

I have observed that "stick" type gauges seem as a group to be the most likely to lose calibration. This is because of dirt etc getting on the "stick" part as well as general wear.

Might have something to do with where & how you store such a gauge. If you throw it in an old tool box with a bunch of grimy tools, well, yeah.

Mine is stored inside the coach when not in use, wrapped up in a towel to keep it nice & clean.

[buddy110]

Originally Posted by Nowabeachbum

If you have the space, I would go with a separate 150lb air compressor. They are inexpensive, you don’t start up the coach and they are there for other things like bicycle tires and it is portable so you can take it anywhere. JMHO

Agree. I have a small 150psi pancake compressor that I store in the drivers side front compartment.

[B-Man49]

We have a 2020 Anthem with 365/70's on the front axle. With the weight that we carry we require 110psi (full-timers). I fill the tires from the coach air. I prefer coach air since it has gone through the air dryer.

[GrantP]

Look into an SMC air doubler. About as good a sliced bread. I mounted one on our Essex and then on our London Aire. Basically doubles the pressure of the coach air and fills up tires in a snap to higher pressure. No need for hauling around an additional compressor if space is an issue.

[Anthem46]

Originally Posted by Rocky40067

Need advice on best way to inflate my steer tires (365 x 70) to the Entegra recommended 125 psi. My onboard just can't get there, and looking into buying compressor that will do the job. Will the Viair 450rv be able to do the job?

I run 105 to 110 in my 365.